Analysis of Non-innocence of Phosphaquinodimethane Ligands when Charge and Aromaticity Come into Play.

Several phosphaquinodimethanes and their M(CO) complexes (M=Cr, Mo, W) and model derivatives have been theoretically investigated regarding the quest of non-innocence. Computed structural and electronic properties of the P-Me/NH substituted phosphaquinodimethanes and tungsten complexes revealed an interesting non-innocent ligand behaviour for the radical anion complexes with distonic ion character and a strong rearomatization of the middle phenyl ring. The latter was further probed taking also geometric aromaticity (HOMA) and quinoid distortion parameters (HOMQc) into account, as well as NICS(1).

M/X Phosphinidenoid Metal Complex Chemistry.

ConspectusLike singlet carbenes and silylenes, transient electrophilic terminal phosphinidene complexes enabled highly selective synthetic transformations, but the required multistep synthetic protocols precluded widespread use of these P building blocks. By contrast, nucleophilic M/Cl phosphinidenoid complexes can be easily accessed in one step from [M(CO)(RPCl)] complexes. This advantage and the mild reaction conditions opened broad synthetic applicability that enabled access to a variety of novel compounds.

A case study on the conversion of Li/Cl phosphinidenoid into phosphinidene complexes.

N,N-Diphenylamino- and N,N-dicyclohexylamino-substituted dichlorophosphane W(CO) complexes 1a,b were used to generate thermally very labile Li/Cl phospinidenoid W(CO) complexes 2a,b. The formation of transient complex 2a was confirmed via low-temperature P{H} NMR spectroscopy, but further strong evidence for the formation of transient complexes 2a,b was obtained from reactions with methanol and methylamine as formal E-H insertions (E = O, N) furnished complexes 3a,b and 4a. By using toluene in the absence of donor ligands, the primarily nucleophilic complexes 2a,b were converted into electrophilic terminal phosphinidene complexes 5a,b which was deduced from specific trapping reactions using tolane, 1-pentene and 1-hexene and thus obtained 1H-phosphirene 6 and phosphirane complexes 7 and8.

Formation and properties of phosphaquinomethane tungsten(0) complexes - isolation and conversion of primary radical coupling products.

A rational approach to phosphaquinomethane metal(0) complexes, based on dearomatization of the phenylene unit in [W(CO)](R)P(Cl)-CH-CPh, is described, including theoretical studies on mechanisms and structures. Furthermore, the first phosphaquinone tungsten complex with reversible redox properties is reported thus illustrating the beneficial stabilization of ligation.

Competitive or sequential reaction of an electrophilic terminal phosphinidene metal(0) complex with allyl halides? [2+1]-cycloaddition vs. C-X bond insertion.

The transiently generated electrophilic terminal phosphinidene complex [(CO)WPCH(SiMe)] reacted with allyl halides (X = F, Cl, Br) in toluene resulting in the formation of stable C-X insertion products 3a-c and diastereomeric phosphirane complexes 4a,a',b,b' as well as methylenephosphirane complex 5 as observed by P{H} NMR spectroscopy. DFT calculations revealed that a novel rearrangement of transient phosphirane complexes is responsible involving C → P X atom transfer.

Neoadjuvant Therapy of Cervical Carcinoma with the Angiogenesis Inhibitor Bevacizumab: a Single-Centre Analysis.

Cervical cancer is the fourth most frequent cancer in women worldwide. Addition of the VEGF antibody bevacizumab in combination with platinum-containing chemotherapy achieved an improvement in overall survival in advanced cervical cancer. To date there are no data on neoadjuvant use of bevacizumab.